Return-Air Filters; Outdoor-Air Inlet Screens; Compressor Mounting; Internal Wiring - Carrier WeatherMaker 48TC Series Service And Maintenance Instructions

WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Disconnect gas piping from unit when pressure testing at pres-
sure greater than 0.5 psig (3450 Pa). Pressures greater than
0.5 psig will cause gas valve damage resulting in hazardous
condition. If gas valve is subjected to pressure greater than
0.5 psig, it must be replaced before use. When pressure testing
field-supplied gas piping at pressures of 0.5 psig or less, a unit
connected to such piping must be isolated by closing the man-
ual gas valve(s).
WARNING
If the information in this manual is not followed exactly, a fire
or explosion may result causing property damage, personal in-
jury or loss of life.
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire
department.
Installation and service must be performed by a qualified in-
staller, service agency or the gas supplier.
AVERTISSEMENT
RISQUE D´INCENDIE OU D´EXPLOSION
Si les consignes de sécurité ne sont pas suivies à la lettre, cela
peut entraîner la mort, de graves blessures ou des dommages
matériels.
Ne pas entreposer ni utiliser d´essence ni autres vapeurs ou liq-
uides inflammables à proximité de cet appareil ou de tout autre
appareil.
QUE FAIRE SI UNE ODEUR DE GAZ EST DÉTECTÉE
• Ne mettre en marche aucun appareil.
• Ne toucher aucun interrupteur électrique; ne pas
utiliser de téléphone dans le bâtiment.
• Quitter le bâtiment immédiatement.
• Appeler immédiatement le fournisseur de gaz en
utilisant le téléphone d´un voisin. Suivre les
instructions du fournisseur de gaz.
• Si le fournisseur de gaz n´est pas accessible, appeler le
service d´incendie.
L´installation et l´entretien doivent être effectués par un instal-
lateur ou une entreprise d´entretien qualifié, ou le fournisseur
de gaz.

Return-Air Filters

Ensure correct filters are installed in unit (see Appendix B - Physi-
cal Data). Do not operate unit without return-air filters.

Outdoor-Air Inlet Screens

Outdoor-air inlet screen must be in place before operating unit.

Compressor Mounting

Compressors are internally spring mounted. Do not loosen or re-
move compressor hold down bolts.

Internal Wiring

Check all electrical connections in unit control boxes. Tighten as
required.

Refrigerant Service Ports

Each unit system has two
service ports: one on the suction line, and one on the compressor
discharge line. Be sure that caps on the ports are tight.

Compressor Rotation

On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine
whether or not compressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pressure
should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pressure
does not rise to normal levels:
4. Note that the evaporator fan is probably also rotating in the
wrong direction.
5. Turn off power to the unit and install lockout tag.
6. Reverse any two of the unit power leads.
7. Re-energize to the compressor. Check pressures.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direction,
the unit will make an elevated level of noise and will not provide

cooling.

Cooling
Set space thermostat to OFF position. To start unit, turn on main
power supply. Set system selector switch at COOL position and
fan switch at AUTO. position. Adjust thermostat to a setting be-
low room temperature. Compressor starts on closure of contactor.
Check unit charge. Refer to Refrigerant Charge section.
Reset thermostat at a position above room temperature. Com-
pressor will shut off. Evaporator fan will shut off after a
30 second delay.
To shut off unit, set system selector switch at OFF position. Reset-
ting thermostat at a position above room temperature shuts unit off
temporarily until space temperature exceeds thermostat setting.

Main Burners

Main burners are factory set and should require no adjustment.
To check ignition of main burners and heating controls, move
thermostat setpoint above room temperature and verify that the
burners light and evaporator fan is energized. Check heating ef-
fect, then lower the thermostat setting below the room temperature
and verify that the burners and evaporator fan turn off.
Refer to Tables 16 and 17 for the correct orifice to use at high
altitudes.

Heating

1. Purge gas supply line of air by opening union ahead of the gas
valve. If gas odor is detected, tighten union and wait
5 minutes before proceeding.
2. Turn on electrical supply and manual gas valve.
70
/ -in. SAE flare (with check valves)
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